Recent studies have shown that, at present, 80% of the pharmaceuticals being globally developed are biological products such as bio-therapeutic agents (e.g., vaccines) or biological supplies/samples (e.g., blood, serum etc.). These products typically cost ten times more than traditional products to handle during manufacture and transport through the supply chain. These additional costs arise because biological products are often sensitive to environmental conditions and thus require specialised handling. For instance, many biological products (e.g., enzymes) are temperature-sensitive and must be handled and stored at low temperatures. Similarly, other biological products are sensitive to the presence of oxygen or other ambient gases. Consequently, these products must be handled and stored in an air-free environment. If a biological product is exposed to a particular environmental condition or agent during manufacture, storage or transport, the biological product may react therewith and decay more rapidly than predicted by its official expiration date. Consequently, the safety of such products is brought into doubt.
To further complicate the matter, biological products are typically transported in smaller quantities than traditional products. It is also envisaged that even smaller quantities of these products will be routinely transported in the future. Consequently, a major problem facing the pharmaceutical industry is improving control over the handling of biological products whilst lowering their overall transport cost.
Security seals can be roughly divided into three types, namely tamper-evident seals, barrier seals and electronic seals. Tamper-evident seals do not secure items against tampering. Instead, a tamper-evident seal provides evidence of ingress or contamination of an item to which it is attached. Tamper-evident seals are typically simple seals such as frangible foils or films, crimped cables or other (theoretically) irreversible mechanical assemblies. Tamper detection is typically based on a manual inspection of the tamper evident seal. However, whilst this process is acceptable for a small number of items, it is not practical or reliable for a large number of items.
In contrast with tamper-evident seals, electronic security seals actively monitor for tampering and provide a real-time alert in the event that tampering occurs. Consequently, electronic security seals facilitate rapid, convenient and cost-effective control over the handling and storage of an item without requiring manual intervention.
Electronic security seals typically require a source of power. For instance, U.S. Pat. No. 5,111,184 describes a device in which a fiber optic cable is connected between a fixed member and a movable member of a container so that the cable is bent when the container is opened and closed. Light pulses are transmitted through the cable and variations in the pulses resulting from bending of the cable are detected to indicate the opening and closing of the container. The device in U.S. Pat. No. 5,111,184 is powered by a battery pack. However, the inclusion of a power supply in an electronic security seal increases the cost, size and weight of the seal.
Passive RFID tags do not have their own power supply. Instead, these devices possess an antenna that captures the power from an incoming radio-frequency (RF) scan (in the form of a minute electrical current induced in the antenna). This provides enough power for the tag to send a response to the received RF scan. Since a passive RFID tag does not need its own power supply, a tag can be designed with very small dimensions. For instance, U.S. Pat. No. 6,275,157 describes an RFID transponder that is embedded in the glass of a vehicle windshield.
U.S. Pat. No. 6,720,866 describes an RFID tag device with a sensor input adapted to receive variable signals from a switch(es), an analog variable or a digital variable. Whilst the device described in U.S. Pat. No. 6,720,866 could be adapted to include a sensor specifically designed to detect the opening of a container, it would also be necessary to include several logic circuits to handle the signals therefrom. However, the inclusion of these logic circuits would make the device quite complex and thus expensive to manufacture.
WO02095655 describes a tamper-indicating label comprising a tamper track coupled to an RFID component. In one embodiment, the adhesion characteristics of the tamper track are adapted to break apart the tamper track when the label is tampered with. In a similar vein, CA2417616 describes a tamper-indicating RFID label designed to permit the destruction of the label in the event of an attempt to remove the label from a surface. In particular, an adhesion modifying coating is applied to portions of the label to affect the relative adhesion strength therebetween and thereby enable differential separation of the label from a surface in the event of an attempt to remove the label therefrom.
Systems such as those described in CA2417616 and WO02095655 could be used to detect the removal of a container cap by applying the label to the container so that one part of the label is attached to the cap and the other part is attached to the container. With this arrangement, the label must be peeled off the container in order to remove the cap. However, these systems detect the removal of the label, rather than the specific operation of opening the container. Consequently, these systems may be less secure than a system based on the direct detection of the opening of a container. On the other hand, a very complex label manufacturing and fixing process would be needed to enable the direct (absolute) detection of container opening.